Protein localization by actin treadmilling and molecular motors regulates stereocilia shape and treadmilling rate.
We present a physical model that describes the active localization of actin-regulating proteins inside stereocilia during steady-state conditions. The mechanism of localization is through the interplay of free diffusion and directed motion, which is driven by coupling to the treadmilling actin filaments and to myosin motors that move along the actin filaments. The resulting localization of both the molecular motors and their cargo is calculated, and is found to have an exponential (or steeper) profile. This localization can be at the base (driven by actin retrograde flow and minus-end myosin motors), or at the stereocilia tip (driven by plus-end myosin motors). The localization of proteins that influence the actin depolymerization and polymerization rates allow us to describe the narrow shape of the stereocilia base, and the observed increase of the actin polymerization rate with the stereocilia height.
Naoz
Moshe
M
Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.
Manor
Uri
U
Sakaguchi
Hirofumi
H
Kachar
Bechara
B
Gov
Nir S
NS
D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D022081:Cell Surface Extensions / Q000378:metabolism*; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D009068:Movement; D009218:Myosins / Q000378:metabolism; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D021381:Protein Transport
D000199:Actins; D020409:Molecular Motor Proteins; D009218:Myosins